Bug 19106

Summary: Corruption of xl driver's TX chain during startup
Product: Base System Reporter: Justin T. Gibbs <gibbs>
Component: kernAssignee: Bill Paul <wpaul>
Status: Closed FIXED    
Severity: Affects Only Me    
Priority: Normal    
Version: Unspecified   
Hardware: Any   
OS: Any   

Description Justin T. Gibbs freebsd_committer freebsd_triage 2000-06-07 21:30:00 UTC 
Some time after the exit of xl_attach, the 9th entry in
sc->xl_cdata.xl_tx_chain gets corrupted.  From GDB:

sc->xl_cdata.xl_tx_chain[9] = {xl_ptr = 0x0, xl_mbuf = 0x2020000,
 xl_next = 0x0, xl_prev = 0x202, xl_phys = 0}

This causes a panic in m_freem when xl_stop() is called during
the first ioctl call that occurs during network startup.

Clearing this garbage from the debugger is enough to get the system
up and from that point on, it appears to be stable.

Fix: 

I'm still trying to track down the source of the corruption, but I
currently have no fix.
How-To-Repeat: Boot my system.
Comment 1 Jeroen Ruigrok van der Werven freebsd_committer freebsd_triage 2000-06-11 12:23:11 UTC 
Responsible Changed
From-To: freebsd-bugs->wpaul

xl driver maintainer.
Comment 2 Justin T. Gibbs freebsd_committer freebsd_triage 2000-10-05 04:04:48 UTC 
State Changed
From-To: open->closed

No longer reproducible.